From owner-freebsd-questions@FreeBSD.ORG Mon Aug 21 16:42:54 2006 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C214E16A4DA for ; Mon, 21 Aug 2006 16:42:54 +0000 (UTC) (envelope-from savage@savage.za.org) Received: from ctb-mesg4.saix.net (ctb-mesg4.saix.net [196.25.240.74]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3990D43D49 for ; Mon, 21 Aug 2006 16:42:53 +0000 (GMT) (envelope-from savage@savage.za.org) Received: from superman (dsl-146-243-05.telkomadsl.co.za [165.146.243.5]) by ctb-mesg4.saix.net (Postfix) with ESMTP id E91C02D24; Mon, 21 Aug 2006 18:42:48 +0200 (SAST) Message-ID: <003701c6c540$d0744f20$0a01a8c0@superman> From: "Chris Knipe" To: "Dan Nelson" References: <000701c6c539$bbb33710$0a01a8c0@superman> <20060821162156.GB45306@dan.emsphone.com> Date: Mon, 21 Aug 2006 18:42:34 +0200 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2962 Cc: freebsd-questions@freebsd.org Subject: Re: sluggish disk performance. X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Chris Knipe List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Aug 2006 16:42:54 -0000 > In the last episode (Aug 21), Chris Knipe said: >> Disks ad0 ofod intrn >> KB/t 16.83 %slo-z 35456 buf >> tps 103 4 tfree 414 dirtybuf >> MB/s 1.70 20988 desiredvnodes >> % busy 98 5247 numvnodes >> 4223 freevnodes >> >> Got 1 ATA100 Seagate 120GB disk in there at the moment.... 1.7MB/s at >> 98% busy? Surely, that figure is WAY low??? I'd expect atleast >> about 10MB/s on ATA100. > > That number's about right for random I/O and small blocksizes, which is > what the KB/t field shows. If you were doing sequential I/O, the KB/t > field would be at or near 128. Are you also running a "du", "cvs > update", or other command likely to be doing random disk accesses? ALTER TABLE on a 200MB mySQL table? I guess its time for a dedicated disk then.... -- C